We studied the efficacy of an immunosuppressive agent, cyclosporine A (CSA) in the treatment of severe, recalcitrant psoriasis and/or psoriatic arthritis unresponsive to existing therapies. The mechanism of action of CSA in psoriasis appears to be related to modulation of lymphocyte activity via an effect on inflammatory mediators (lymphokines) Using skin biopsies obtained before and after treatment, we looked for the expression of lymphokine genes in lesional skin and studied the effect of CSA therapy on lymphokine production and also tried to determine if CSA induces reveals in epidermal and immune activation in psoriatic plaques.